Electric oscillation circuit



Feb. 25, 1936. H, MUTH ELECTRIC OSCILLATION CIRCUIT Filed April 19. 1930BY 1 INVENTOR E M5/W ATTORNEY Patented Feb. 25, 1936 UNITED STATESPATENT OFFICE 2,031,846- ELECTRIC OSCIILATION CIRCUIT Herbert Muth,Berlin, Germany, assignor to Telefunken Gesellschaft fur DrahtloseTelegraphie m. b. H., Berlin Germany, a corporation of GermanyApplication April 19, 1930, Serial No. 445,599 In Germany May 24, 192913 Claims. (Cl. Z50-40) form (deformations) as due to the thermal co`eiiicient of expansion of the materials used in the presence of heatvariations, are required. Now, in order that these changes in form maybe kept inside small limits, only materials possessing an extremelysmall coeiilcient of thermal expansion are used. In viewv of the factthat metal alloys having a small heat expansion coefilclent (such asInvar) are difllcult to work so into the desired form and when so workedoften are subject to internal strains which affect their operativeness,recourse is had according to this invention to the use of insulators ornon-conductors possessing a low temperature coeiilcient, such as fusedquartz, porcelain, or steatite which are covered externally withametallic coatso that their surfaceisrenderedconductive.Materialssuitable for covering the non-conductor are copper and silver,because of their high conducting power. In a preferred form the copperor silver coated nonconductor may be given an additional coating of goldor platinum in order to protect the conducting film from atmosphericeffects. The said coatings may be applied by any desired method, say,ceramically or electrolytically, or by both these processes. Therequisite thickness of the film is governed by the frequencies to beused since it depends upon the depth of penetration of the alternatingcurrent into the material in question. For high frequencies it need notbe over a few hundrdths of one millimeter thick.

The manner in which the present invention is carried out will be readilyapparent from the following description of a specific embodiment of thesame. In the drawing:

Fig. 1 is a diagrammatic view of an oscillation circuit partly insection; and

Fig. 2 is a cross-sectional view of the conductors used in the circuitof Fig. 1, the proportions being exaggerated for the sake of clarity.Referring in detail to the drawing the leads I3 and coil I0 comprise anon-conducting core II and a conducting coating I2 applied thereto asshown in Fig. 2. The leads Il of the same structure as the coil I0connect the coil to a condenser I 4. I'he condenser I4 is made up ofnon-conducting plates I5 coated by the conducting material I2. Anysuitable leads I6 may connect the oscillation circuit to the apparatuswith which it is to be used.

Having thus described my invention, I claim:

l. A radio frequency relay circuit the conductors inductance andcondenser plates of which are composed of a hard, solid non-conductingmaterial, a continuous layer of conducting ma- 10 terial on saidnon-conducting material, and a continuous layer of chemically inactiveconductive material on said last named layer of conducting material.

2. An oscillation circuit the capacitive and in- 15 ductlve elements ofwhich are of a solid, nonconducting and hard base material, a continuouslayer of copper superposed on said non-conducting base material, and acontinuous layer of gold over said layer of copper. 2

3. An oscillation circuit including a tuning capacity, said capacitybeing composed of physically separated plates of non-conductingmaterial, a layer of conducting material over said non-conductingmaterial, and a layer of chemically inactive conducting material oversaid first named layer of conducting material.

4. An oscillation circuit including an inductance coil comprised of abase of non-conducting material'possessing a relatively low temperature30 coenicient as compared with metals such as copper, and a continuouslayer of conducting material superposed upon said base, in parallelrelationship with a condenser comprised of two physically separatednon-conducting plates of quartz 35 having superposed thereon highlyconducting material such as copper or silver.

5. An oscillation circuit comprising an inductance having a singlecontinuous core of solid non-conducting material, a continuous layer of40 conducting material superposed on and fixed to` said core, and alayer of chemically inactive conducting material over said firstmentioned layer of conducting material.

6. An oscillation circuit comprising an in- 5 ductance having a singlecontinuous helical core of solid non-conducting material, a thincontinuous layer of conducting material superposed on and fixed to saidhelical core, and a layer of chemically inactive conducting materialover said 50 first mentioned layer of conducting material.

' 7. An oscillation circuit comprising an inductance having a singlecontinuous helical core ,y of solid non-conducting material, a condenserVcomprising two physically separated non-conducting platea'a thincontinuous layer of metal surrounding said helical core and saidnon-conducting plates, and conductive means for connecting in parallelrelationship said inductance and said condenser.

8. .An oscillation circuit comprising an inductance having a singlecontinuous helical core of solid non-conducting material, a condensercomprising two physically separated non-conducting plates, a thincontinuous layer of metal surrounding said helical core and saidnon-conducting plates, a, plurality of rod-like members having a similarmetallic coating as said inductance and said condenser for connecting inparallel relationship said inductance and said condenser. g

9. An inductor comprising a conductor disposed in a coil of at least oneturn, said conductor having a core of material having a low coefcient ofthermal expansion xed to a shell of conducting material having a highelectrical conductivity and a relatively high coefficient of expansion.

10. An inductor comprising a conductor disposed in a coil of at leastone turn, said conductor having a core of relatively low coemcient yoi"expansion and high rigidity, and a conducting shell fixed to said coreand constrained thereby against expansion in the direction of the lengthof the core.

11. An inductor comprising a conductor disposed in a coil of at leastone turn, said conductor having a core of nonconducting material havinga low coeiiicient of thermal expansion ilxed to a shell of conductingmaterial having a high electrical conductivity and a relatively highcoefilcient of thermal expansion.

12. An inductance coil characterized by having a substantially constantinductance under varying temperatures, comprising at least one turn of aquartz rod plated with metal of high conductivity and having a highcoeicient 'of thermal expansion.

13. The method'of maintaining the inductance of a coiled conductorhaving a shell of material of a high coeiicient of thermal expansionconstant under varying temperatures, which comprises restricting thelongitudinal expansion of said shell without interfering with thediametrical expansion of said shell.

HERBERT MUTH.

